DIY Off-Grid Systems
Larger scale off-grid systems normally require the involvement of a professional electrician to ensure a safe and compliant installation. However, if basic procedures are followed very successful wind & solar systems can be self installed. Indeed, sometimes in remote areas there may be no choice!
Often DIY installation can reduce costs and can also mean users understand their systems better, so gaining most benefit from them.
However, electricity & wiring may not be for everyone, can be dangerous, and mistakes can be expensive! So, if in doubt and particularly for larger systems, an experienced electrician or installer should supervise or undertake the work.
In all cases systems should be installed according to local electrical and other safety codes.
DIY 12 and 24 V DC Systems
These are typically used on remote buildings to power 12V lighting and low consumption appliances or in situations where an existing battery based system is in place (e.g.. vehicles, boats & caravans) or to run small dedicated loads (e.g.. remote lighting, telemetry or monitoring equipment).
The wind generator or solar PV panels charge the battery and the battery supplies power to the loads as needed. All loads are run at the battery voltage (usually 12 or 24 VDC) and special lights or appliances are needed. The charging source is sized to keep up with anticipated demand.
Typical DC loads include:
- Phone charging;
- TV; radio;
To be successful, efficient use of the electricity generated is essential and the system must be sized to meet worst case conditions.
Small Solar Only System
A good system for providing lighting in buildings where lighting is either only needed occasionally or mainly during summer months such as holiday cabins or garden sheds.
Uses: 50Wp photovoltaic module; wall/roof mounting bracket; 6m output cable; charge controller; 12V 75Ah battery; battery terminals; 2 x LED lights; interconnect cables.
Budget Cost: approx. £320.00 + Vat
Small Wind Only System
Typically used for systems such as providing stable lighting - where the building is in open countryside and gets good exposure to the wind. Lighting is needed most over winter months when output from the wind generator is greatest.
Uses: Marlec 913 wind generator; gable end mounting pole kit; 10m output cable; control unit; 90Ah battery; battery terminals. interconnect cables.
Budget Cost: approx. £750.00 + Vat
PV Solar Panels
For many systems 12V Small Area Modules which vary in size from 5 - 150 W are used with standard charge controllers.
Where more space is available standard PV panels (250W upwards) can be used with MPPT charge conrtrollers.
Greatest output will be over summer months so this is ideal for holiday, weekend or garden buildings. No moving parts are involved so such systems are almost maintenance free.
The simplest systems use a photovoltaic (PV) solar panel to recharge the battery. This can be easily fitted to the roof or a sunny wall of the building using simple brackets.
These regulate the amount of energy going into the battery, preventing them from overcharging. Some include a low voltage warning or disconnect function to switch off loads to prevent battery damage from excessive discharge.
Maximum Power Point Tracking (MPPT) charge controllers enable the use of standard roof-top panels to be used for charging 12 or 24 V batteries.
For year round use wind generators are ideal for providing lighting since maximum output tends to be over winter when lighting is needed most. Small wind generators can often be easily mounted on the end of a building using TV aerial type brackets and pole. Power is fed down to the battery via a charge controller and then on to the loads. See: Marlec and Leading Edge wind generators.
This stores power generated during the day to run loads at night or during inclement weather conditions. Different sizes are available to suit different sized systems.
Usually, 12V lead acid batteries are used which can be connected together either in parallel (to increase capacity) or series (increasing both capacity and voltage).
These can be included to provide 230 Vac ‘mains’ power, enabling conventional tools or appliances to be run. However, they introduce potentially dangerous hazards and voltages so, it is often advisable for an experienced electrician or installer to supervise or undertake the wiring.
See: Victron inverters
Monitoring & Circuit Protection
Meters, to monitor system operation enable optimum performance.
Fuses or circuit breakers to protect wiring should be included.